solve: 코딩테스트 문제 풀이 - 25일차

Author: OhChangEun

2025-09-06/오창은/[solved] 백준_다리 놓기.java

@@ -0,0 +1,28 @@
+import java.io.*;
+
+public class Main {
+    static final int MAX = 30;
+    static int[][] dp = new int[MAX + 1][MAX + 1];
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int T = Integer.parseInt(br.readLine());
+
+        for (int n=0; n <= MAX; n++) {
+            dp[n][0] = 1;
+            dp[n][n] = 1;
+
+            for (int r=1; r < n; r++) {
+                dp[n][r] = dp[n-1][r-1] + dp[n-1][r];
+            }
+        }
+
+        while(T-- > 0) {
+            String[] parts = br.readLine().split(" ");
+            int N = Integer.parseInt(parts[0]);
+            int M = Integer.parseInt(parts[1]);
+
+            int result = dp[M][N];
+            System.out.println(result);
+        }
+    }
+}

2025-09-06/오창은/[solved] 백준_연속합.java

@@ -0,0 +1,39 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class Main {
+    static int[] arr;
+    static int[] sum;
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int n = Integer.parseInt(br.readLine());
+
+        arr = new int[n];
+        sum = new int[n + 1];
+        String[] parts = br.readLine().split(" ");
+        for (int i=0; i<n; i++) {
+            arr[i] = Integer.parseInt(parts[i]);
+        }
+
+        for (int i=1; i<=n; i++) {
+            sum[i] = sum[i-1] + arr[i-1];
+        }
+
+        int max = Integer.MIN_VALUE;
+        int minPrefix = 0;
+        for (int i = 1; i <= n; i++) {
+            max = Math.max(max, sum[i] - minPrefix);
+            minPrefix = Math.min(minPrefix, sum[i]);
+        }
+
+        System.out.println(max);
+
+        /*
+        for (int num: sum) {
+            System.out.print(num + " ");
+        }
+         */
+        System.out.println();
+    }
+}

2025-09-06/오창은/[solved] 프로그래머스_124 나라의 숫자.java

@@ -0,0 +1,19 @@
+class Solution {
+    public String solution(int n) {
+        StringBuilder sb = new StringBuilder();
+        
+        while (n > 0) {
+            int remainder = n % 3;
+            n /= 3; 
+            
+            if (remainder == 0) {
+                remainder = 4; 
+                n -= 1;
+            }
+            
+            sb.append(remainder);
+        }
+        
+        return sb.reverse().toString();
+    }
+}